A temperature-controlled solar oven with phase change heat storage

Abstract

The present invention relates to a temperature-controlled solar oven with phase-change heat storage, comprising: a concentrating heat collection device consisting of a hot water tank, a concentrating heat collection assembly, and a direction control assembly for heating the working fluid in the hot water tank; a phase-change heat storage device consisting of a housing with universal wheels for the heat storage tank and a series of parallel modular boxes disposed within the housing for storing heat from the working fluid flowing out of the hot water tank; and a multifunctional drying device comprising a drying box and a collection water tank disposed above the drying box. The collection water tank is connected to the phase-change heat storage device and the hot water tank, respectively, to provide heat to the drying box. Compared with existing technologies, the present invention offers advantages such as stepped temperature control, efficient heat collection and drying, novel structure, simplicity and reliability, safety and efficiency, and strong practicality.

Description

Technical Field

[0001] The present invention relates to the field of renewable energy utilization, and in particular to a temperature-controlled solar oven with phase-change heat storage. Background Art

[0002] With the depletion of traditional non-renewable energy, problems such as the deterioration of the global climate have followed one after another, and the environment in which human beings live is seriously threatened. Solar energy has broad application prospects due to its advantages such as cleanliness, safety and energy saving. However, solar energy is affected by factors such as weather and geographical environment, and its energy utilization rate is unstable and its energy density is low.

[0003] Increasing the utilization of renewable energy has become a key development trend in the future energy sector. Therefore, exploring the use of solar energy in energy conservation and environmental protection is crucial for resolving the energy crisis. Currently, the mainstream development direction is to fully utilize the advantages of solar energy in areas with long sunshine hours and ample daylight. However, the intermittent and unstable nature of solar energy still hinders its application. Therefore, it is necessary to develop a temperature-controlled solar oven with phase change heat storage. This oven can utilize clean and environmentally friendly solar energy as its energy supply. At the same time, the use of phase change modules can also improve the stability of the equipment's energy output, achieving the desired effect of drying and heating various agricultural products and Chinese medicinal materials.

[0004] A Chinese patent (application number 201620202984.6) proposes an in-tube phase-change energy storage solar dryer, which absorbs solar energy through a heat pipe and provides heat to a drying box, while the excess heat is absorbed by a waste heat recovery heat exchanger. This device can, to a certain extent, solve problems such as food drying and providing household hot water. However, the dryer lacks a large-capacity heat storage device and cannot guarantee continuous drying processing throughout the day. In particular, the normal operation of the drying equipment cannot be guaranteed under conditions of insufficient sunlight, making it unsuitable for large-scale promotion and application. In addition, a Chinese patent (application number 201010600814.0) proposes a dried fruit and tea drying device based on a double-drum phase-change radiator. This device is conducive to drying tea and agricultural products, but the patent has poor temperature control effect and cannot dry agricultural products around the clock. Summary of the Invention

[0005] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art and provide a temperature-controlled solar oven with phase change heat storage. The present invention efficiently collects solar energy and stores solar heat in a phase change heat storage device. By adjusting the number of heat storage modules and controlling the flow rate of the circulating working fluid, the oven temperature can be continuously controlled for dehumidification and drying. It can be widely used in drying crops or Chinese medicinal materials, domestic hot water and heating systems, etc.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] A temperature-controlled solar oven with phase change heat storage, comprising:

[0008] Concentrating heat collection device: It consists of a hot water tank, a concentrating heat collection component and a direction control component, and is used to heat the working medium in the hot water tank;

[0009] Phase change heat storage device: It consists of a shell with universal wheels for heat storage tank and a series of parallel module boxes arranged in the shell, which is used to store heat from the working fluid flowing out of the hot water tank;

[0010] The multifunctional drying device comprises a drying box and a collecting water tank arranged on the drying box. The collecting water tank is respectively connected to the phase change heat storage device and the hot water tank to provide heat to the drying box.

[0011] The concentrating heat collecting assembly includes a concentrating plate and concentrating support rods respectively used to support and connect the concentrating plates. The top ends of the concentrating support rods are connected to the bottom of the hot water tank, and the bottom ends are respectively connected to the four corners of the concentrating plate.

[0012] The direction control component includes an azimuth motor, a pitch angle motor, brackets installed at both ends of the bottom of the focusing plate, a photosensitive array and a single-chip microcomputer. A connecting rod is provided between the brackets, and a first gear is eccentrically installed on the connecting rod. The output shaft of the azimuth motor is fixed with a turntable, the pitch angle motor is fixed on the turntable, and the output shaft of the pitch angle motor is meshed with the first gear through a second gear for transmission. The mounting bracket is fixed at the bottom of the focusing plate, the load-bearing rod is used to fix the focusing plate, and the photosensitive array is fixed on the load-bearing rod and communicates with the single-chip microcomputer to control the start and stop of the azimuth motor and the pitch angle motor.

[0013] The light concentrating plate is an off-axis and off-focus light concentrating plate formed by separate metal stamping.

[0014] Each module box string is composed of multiple module boxes connected in series, which are connected to the outlet pipe of the hot water tank through the diversion water pipe and the first water inlet pipe, and are connected to the collecting water tank through the first water outlet pipe. Each module box is provided with a heat exchange tube, and the remaining space is filled with composite phase change material.

[0015] The drying box is provided with a low-temperature box, a medium-temperature box and a high-temperature box from bottom to top. The low-temperature box is provided with a low-temperature water pipe, the medium-temperature box is provided with a medium-temperature water pipe, and the high-temperature box is provided with a high-temperature water pipe. The low-temperature water pipe, the medium-temperature water pipe and the high-temperature water pipe are connected in parallel with each other, and their water inlet ends are connected with the second water outlet of the collecting water tank, and the water outlet ends are connected with the third water inlet pipe of the collecting water tank, the third water outlet pipe of the collecting water tank is connected with the water inlet pipe of the hot water tank, and the second water inlet pipe of the collecting water tank is connected with the first water outlet pipe.

[0016] The diameters of the low-temperature water pipe, the medium-temperature water pipe and the high-temperature water pipe increase in sequence, and control valves are respectively provided at the water inlet ends.

[0017] The diameter of the low-temperature water pipe is in the range of 8 to 12 mm, the diameter of the medium-temperature water pipe is in the range of 12 to 16 mm, and the diameter of the high-temperature water pipe is in the range of 16 to 20 mm.

[0018] The composite phase change material adopts a phase change material with a phase change temperature of 50-300°C, a phase change latent heat of 150-300 kJ / kg, and a supercooling degree of 0.1-10°C.

[0019] The four corners and the center area of ​​the module box are provided with openings for installing R-type thermal resistors for temperature measurement.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] 1) The present invention adopts an off-axis and off-focus concentrating heat collecting device that tracks the sun in real time, which can efficiently collect solar heat to heat the hot water tank at the focus of the concentrating plate, providing a heat source for drying and heating.

[0022] 2) The phase change heat storage device consists of several high-performance composite phase change material modules. By adjusting the connection method and number of the heat storage modules, uniform heat output can be achieved around the clock, meeting the drying and heating needs of different agricultural products or Chinese medicinal materials.

[0023] 3) The multifunctional drying device is equipped with multiple layers of heating space. By adjusting the flow of circulating working fluid to maintain different temperatures, it can achieve the effect of stepped temperature control and staged drying. Its drying efficiency is high and stable and reliable.

[0024] 4) The temperature-controlled solar oven with phase change heat storage collects solar heat for heat storage and heats the multifunctional oven, which has high energy utilization rate, good drying effect and strong applicability. It can be widely used in drying crops or Chinese medicinal materials, household hot water systems and household heating. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the present invention.

[0026] Figure 2 It is a structural schematic diagram of the concentrating and heat collecting device of the present invention.

[0027] Figure 3 Schematic diagram of the structure of the phase change heat storage device of the present invention.

[0028] Figure 4 It is a structural schematic diagram of the multifunctional drying device of the present invention.

[0029] Description of the marks in the figure:

[0030] 100, focusing device, 200, phase change heat storage device, 300, multifunctional drying device, 101, azimuth motor, 102, pitch angle motor, 103, mounting bracket, 104, photosensitive array, 105, load-bearing rod, 106, focusing plate, 107, focusing support rod, 108, hot water tank, 201, housing, 202, heat storage tank universal wheel, 203, module box, 204, first water inlet pipe, 205, Diversion water pipe, 206, composite phase change material, 207, first water outlet pipe, 208, heat exchange pipe, 301, second water inlet pipe, 302, collecting water tank, 303, second water outlet pipe 304, third water outlet pipe, 305, high temperature box, 306, high temperature water pipe, 307, medium temperature box, 308, medium temperature water pipe, 309, low temperature box, 310, low temperature water pipe, 311, universal wheel of drying device, 312, third water inlet pipe. DETAILED DESCRIPTION

[0031] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] Example

[0033] like Figure 1 As shown, the present invention provides a temperature-controlled solar oven with phase change heat storage, which includes a concentrating heat collecting device 100, a phase change heat storage device 200 and a multifunctional drying device 300.

[0034] like Figure 2 As shown, the concentrating heat collection device 100 consists of a hot water tank 108, a concentrating heat collection assembly (a azimuth motor 101, a pitch angle motor 102, and a mounting bracket 103 with a connecting rod having a first gear sleeved thereon), and a direction control assembly (a photosensitive array 104, a load-bearing rod 105, a concentrating plate 106, a concentrating support rod 107, and a single-chip microcomputer). The azimuth motor 101 is transmission-connected to the pitch angle motor 102 and is located at the bottom of the concentrating heat collection assembly. The upper ends of the four concentrating support rods 107 are rotatably connected to the bottom of the hot water tank 108 to form a support frame for the concentrating plate 106. The concentrating plate 106 with an off-axis and off-focus configuration is mounted on the bottom of the frame. The concentrating plate 106 focuses on the bottom of the hot water tank 108 for heating. The concentrating plate 106 is reinforced by a load-bearing rod 105. The photosensitive array 104 is fixed on the load-bearing rod 105 to send the collected light intensity information to the single-chip microcomputer. The single-chip microcomputer controls the start and stop of the azimuth angle motor 101 and the pitch angle motor 102 to make the direction of the concentrating plate 106 adapt to the law of sunlight changing over time. That is, the light signal is collected by the photodiode in the photosensitive array 104 and transmitted to the single-chip microcomputer, which then controls the azimuth angle motor 101 and the pitch angle motor 102 to adjust the angle, thereby adjusting the concentrating plate 106 to maximize heat collection.

[0035] When adjusting the azimuth and pitch angles of the focusing plate 106, the azimuth is adjusted first. The vertically mounted azimuth motor 101 is started to drive the turntable mounted on the output shaft. The rotation of the turntable drives the pitch angle motor 102 to rotate, thereby changing the azimuth. When the azimuth is adjusted to the right position, the pitch angle motor 102 is started again to drive the first gear to rotate. The second gear meshes with the first gear and transmits the rotation. Since the second gear is eccentrically assembled with the connecting rod, the rotation of the second gear drives the connecting rod to swing up and down, thereby adjusting the pitch angle.

[0036] like Figure 4 As shown, the phase change heat storage device 200 includes a shell 201, a heat storage tank with universal wheels, a module box 203 arranged in series and parallel inside the heat storage tank, a first water inlet pipe 204, a diversion water pipe 205 and a first water outlet pipe 207. The outlet pipe of the hot water tank 108 is connected to the first water inlet pipe 204, and the diversion water pipe 205 is connected to the first water inlet pipe 204 to connect each module box string. A heat exchange pipe 208 is provided in the module box 203, and the remaining space is filled with a composite phase change material 206. The heat exchange pipe 208 absorbs heat in the composite phase change material 206 through a circulating working medium (water in this example). The heat in the first water inlet pipe 204 is exchanged to the composite phase change material 206 mainly by heat conduction through the diversion water pipe 205, and the diversion water pipe 205 is coated with an insulation material.

[0037] A serpentine distributed heat exchange tube 208 is provided in the module box 203. The hot working medium flows out of the hot water tank 108 and reaches the first water inlet pipe 204, flows through the diversion water pipe 205, and finally flows out from the first water outlet pipe 207. The phase change heat storage device 200 is composed of a plurality of module boxes 203. By adjusting the connection mode and number of the module boxes 203, uniform heat output can be achieved around the clock.

[0038] like Figure 3As shown, the multifunctional drying device 300 consists of a second water inlet pipe 301, a collecting water tank 302, a second water outlet pipe 303, a third water outlet pipe 304, a high-temperature box 305, a high-temperature water pipe 306, a medium-temperature box 307, a medium-temperature water pipe 308, a low-temperature box 309, a low-temperature water pipe 310, a drying device universal wheel 311 and a third water inlet pipe 312; the second water inlet pipe 301 is connected to the first water inlet 207 and enters the second water outlet 303 through the collecting water tank 302. The working medium in the second water outlet pipe 303 flows into the high-temperature water pipe 306, the medium-temperature water pipe 308 and the low-temperature water pipe 310. The working medium circulating in the pipe enters the third water inlet pipe 312, heating the high-temperature box 305, the medium-temperature box 307 and the low-temperature box 309 respectively. Finally, the water flows into the third water outlet pipe 304 through the collecting water tank 302 and returns to the hot water tank 108. The multifunctional drying device 300 obtains heat from the phase change heat storage device 200. By adjusting the flow rate of the circulating working medium to maintain different temperatures, the effect of step temperature control and staged drying can be achieved. The working medium finally returns to the hot water tank 108 along the pipeline, and the pipeline in the phase change heat storage temperature regulation type adaptive solar multifunctional drying oven forms a closed loop.

[0039] The second water inlet pipe 301 is connected to the first water inlet 207 and reaches the second water outlet 303 through the collecting water tank 302. The working medium in the second water outlet pipe 303 flows into the high-temperature water pipe 306, the medium-temperature water tank 308 and the low-temperature water pipe 310. The working medium in the pipe circulates into the third water inlet pipe 312, flows into the third water outlet pipe 304 through the collecting water tank 302, and finally returns to the hot water tank 108. The multifunctional drying device 300 is provided with three layers of heating space: high, medium and low. By adjusting the flow rate of the circulating working medium to the corresponding temperature boxes, the effect of stepped temperature control and staged drying can be achieved, and its drying efficiency is high and stable and reliable.

[0040] The specific working principle of the present invention is as follows:

[0041] In a phase-change heat storage and temperature-regulating adaptive solar multifunctional drying oven, the concentrating solar collector primarily captures heat energy from sunlight and transfers it to the hot water tank. Two motors with different degrees of freedom work in tandem, using a photosensitive array to monitor sunlight intensity in real time. Off-axis, off-focus concentrators automatically track the sun's energy, efficiently converting the absorbed energy into the hot water tank to heat the working fluid. The phase-change heat storage unit is constructed from easily stampable, high-load-resistant stainless steel for its housing. Its double-door design facilitates subsequent valve opening and closing, inspection, and maintenance. The bottom rotor is constructed from thickened steel for enhanced stability, and brake pads facilitate docking the heat storage unit at a designated location. The collected heat energy is primarily converted into a composite phase-change material. The hot working fluid from the hot water tank is transferred to the first inlet pipe, then through the diverter pipe, and finally out the first outlet pipe. This not only stores heat in the composite phase-change material but also transfers it to the multifunctional drying unit. The phase change thermal storage module rationally controls the heat input into the oven through a variety of working conditions. A pagoda joint is set between the module and the oven to connect with the pipeline. The oven is provided with three levels: high, medium and low. The diameters of high, medium and low temperature water pipes are 16-20mm, 12-16mm and 8-12mm respectively. Different pipe diameters can provide stepped temperatures for the oven and achieve the effect of staged drying. Its drying efficiency is high and stable and reliable.

[0042] Obviously, the above embodiments of the present invention are merely examples for the purpose of illustrating the present invention, and are not intended to limit the embodiments of the present invention. Those skilled in the art will appreciate that other variations based on the above description are possible. It is not necessary and impossible to enumerate all embodiments here. However, obvious variations or modifications arising from the essence of the present invention remain within the scope of protection of the present invention.

Claims

1. A temperature-controlled solar oven with phase change heat storage, characterized in that: include: A concentrating heat collecting device (100): composed of a hot water tank (108), a concentrating heat collecting component, and a direction control component, and used to heat the working medium in the hot water tank (108); Phase change heat storage device (200): composed of a housing (201) with heat storage tank universal wheels (202) and a plurality of parallel module tank strings arranged in the housing (201), for storing heat from the working fluid flowing out of the hot water tank (108); The multifunctional drying device (300) comprises a drying box and a water collecting tank (302) arranged on the drying box, wherein the water collecting tank (302) is connected to the phase change heat storage device (200) and the hot water tank (108) respectively to provide heat to the drying box; Each module box string is composed of a plurality of module boxes (203) connected in series, and is connected to the outlet pipe of the hot water tank (108) through a diversion water pipe (205) and a first water inlet pipe (204), and is connected to the collecting water tank (302) through a first water outlet pipe (207). A heat exchange pipe (208) is provided in each module box (203), and the remaining space is filled with a composite phase change material (206); The drying box is provided with a low-temperature box (309), a medium-temperature box (307) and a high-temperature box (305) from bottom to top. The low-temperature box (309) is provided with a low-temperature water pipe (310), the medium-temperature box (307) is provided with a medium-temperature water pipe (308), and the high-temperature box (305) is provided with a high-temperature water pipe (306). The low-temperature water pipe (310), the medium-temperature water pipe (308) and the high-temperature water pipe (306) are connected in parallel with each other, and their water inlet ends are connected to the second water outlet (303) of the collecting water tank (302), and their water outlet ends are connected to the third water inlet pipe (312) of the collecting water tank (302). The third water outlet pipe (304) of the collecting water tank (302) is connected to the water inlet pipe of the hot water tank (108), and the second water inlet pipe (301) of the collecting water tank (302) is connected to the first water outlet pipe (207). The multifunctional drying device (300) is provided with three layers of heating space: high, medium and low, and different temperatures are maintained by adjusting the flow rate of the circulating working medium; The phase-change heat storage device (200) can adjust the connection mode and quantity of the module boxes (203), and reasonably control the heat input into the oven through various working conditions.

2. The temperature-controlled solar oven with phase change heat storage according to claim 1, characterized in that: The concentrating heat collecting assembly comprises a concentrating plate (106) and concentrating support rods (107) respectively used to support and connect the concentrating plates (106); the top ends of the concentrating support rods (107) are connected to the bottom of the hot water tank (108), and the bottom ends are respectively connected to the four corners of the concentrating plate (106).

3. The temperature-controlled solar oven with phase change heat storage according to claim 2, characterized in that: The direction control component comprises an azimuth motor (101), a pitch angle motor (102), brackets (103) mounted at both ends of the bottom of a light collecting plate (106), a photosensitive array (104) and a single chip microcomputer. A connecting rod is provided between the brackets (103), and a first gear is eccentrically mounted on the connecting rod. The output shaft of the azimuth motor (101) is fixed with a turntable. The pitch angle motor (102) is fixed on the turntable. The output shaft of the pitch angle motor (102) is meshed with the first gear through a second gear for transmission. The mounting bracket (103) is fixed at the bottom of the light collecting plate (106). The load-bearing rod (105) is used to fix the light collecting plate (106). The photosensitive array (104) is fixed on the load-bearing rod (105) and communicates with the single chip microcomputer to control the start and stop of the azimuth motor (101) and the pitch angle motor (102).

4. The temperature-controlled solar oven with phase change heat storage according to claim 3, characterized in that: The light collecting plate (106) is an off-axis and off-focus light collecting plate formed by separate metal stamping.

5. The temperature-controlled solar oven with phase change heat storage according to claim 1, characterized in that: The diameters of the low-temperature water pipe (310), the medium-temperature water pipe (308), and the high-temperature water pipe (306) increase in sequence, and control valves are respectively provided at the water inlet ends.

6. The temperature-controlled solar oven with phase change heat storage according to claim 5, characterized in that: The diameter of the low-temperature water pipe (310) ranges from 8 to 12 mm, the diameter of the medium-temperature water pipe (308) ranges from 12 to 16 mm, and the diameter of the high-temperature water pipe (306) ranges from 16 to 20 mm.

7. The temperature-controlled solar oven with phase change heat storage according to claim 1, characterized in that: The composite phase change material (206) adopts a phase change material with a phase change temperature of 50~300°C, a phase change latent heat of 150~300 kJ / kg, and a supercooling degree of 0.1~10°C.

8. The temperature-controlled solar oven with phase change heat storage according to claim 1, characterized in that: The four corners and the center area of ​​the module box (203) are provided with openings for installing R-type thermal resistors for temperature measurement.

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